A convex-lens-shaped lenticular lens array configured with liquid crystals or liquid crystal polymers having optical anisotropy is formed on a concave-lens-shaped transparent polymer layer. A lens function of the concave-lens-shaped lenticular lens array is determined according to a polarization direction of an incident beam. For example, in the case where a refractive index of the concave-lens-shaped polymer layer and an ordinary refractive index of the convex-lens-shaped liquid crystals or liquid crystal polymers formed on the concave-lens-shaped polymer layer are optical matched and an extraordinary refractive index of the liquid crystals or liquid crystal polymers is larger than the reproduction image of the polymer layer, when the incident beam is incident so that the polarization of the incident beam is parallel to the extraordinary refractive index axis direction, the lenticular lens array functions as a convex lens, so that light is focused to be output. However, when the polarization of the incident beam is parallel to the ordinary refractive index axis direction, the lenticular lens array does not function as a convex lens, so that light cannot be focused, and thus, the light propagates straightforward.
When the light having the polarization parallel to the extraordinary refractive index axis direction is incident on the above-described lenticular lens array, an array of focused line pattern having a directionality parallel to an axis direction of the lens array is formed at the point separated by a focal length.
The present invention is to provide an optical device with various focused beam patterns according to polarization of an incident beam using a lenticular lens array having the above characteristics.